1411249 - Missing background behind text on specific page

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect, P1)

Description

[Kartikaya Gupta (email:[e-mail])]

On http://everlastwindowsanddoors.ca/contact-us/ just below the "Contact us" banner there is a bunch of text and the contact form. Without WR this area has a whitish background but with WR enabled the whitish background is not there and instead the page's fixed background image is visible, making the text hard to read.

Comment 1

[Markus Stange [:mstange]]

Attachment: testcase

I reduced this page to just a scrolled clip (using the "clip" property) on a fixed element. This testcase looks very similar to a reftest I remember writing before.
So are scrolled clips on fixed elements just not working with WebRender at the moment?

Comment 2

[Kartikaya Gupta (email:[e-mail])]

Attachment: testcase v2

I updated the reduced testcase to add a "transform: translateZ(0px)" on the fixed-pos item, which is present in the original page. This affects the display list because it introduces an extra nsDisplayTransform wrapper that sits inside the FixedPosition but outside the Background. I had a patch that fixed the first version of the reduced testcase but failed because of the extra nsDisplayTransform, so this test case is more representative of the real page.

Comment 3

[Kartikaya Gupta (email:[e-mail])]

Taking this even though it's a P3 [wr-reserve] because I ended up fixing it as part of my investigation into bug 1408792.

Comment 4

[Kartikaya Gupta (email:[e-mail])]

Attachment: Bug 1411249 - Handle yet more clipping cases.

This extends the fix in bug 1373802 to account for extra levels of
display item nesting. If those extra intermediate display items don't
push any clips we still want to pick up the ClipAndScroll from the
enclosing ancestor that has it.

Review commit: https://reviewboard.mozilla.org/r/194008/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/194008/

Comment 5

[Kartikaya Gupta (email:[e-mail])]

^ This patch applies on top of bug 1373802. Try push that includes both patches: https://treeherder.mozilla.org/#/jobs?repo=try&revision=5bbe693d58de7972add965cdda0b55dc092f43f9

Comment 6

[Markus Stange [:mstange]]

Comment on attachment 8922865 [details]
Bug 1411249 - Handle yet more clipping cases.

https://reviewboard.mozilla.org/r/194008/#review199100

Comment 7

[Kartikaya Gupta (email:[e-mail])]

Comment on attachment 8922865 [details]
Bug 1411249 - Handle yet more clipping cases.

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/194008/diff/1-2/

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/aa6f720f86f0
Handle yet more clipping cases. r=mstange

Comment 9

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/mozilla-central/rev/aa6f720f86f0